Vibration prevention device for bandsaw machines

ABSTRACT

A bandsaw machine which has a sawhead assembly in which a flexible endless bandsaw blade is trained around a pair of bandsaw blade wheels to cut a workpiece, with the blade being guided by a guide arm, includes a guide member on the guide arm, for holding the bandsaw blade in a vertical orientation by pushing the bandsaw blade from both sides. A rolling member is mounted on the sawhead assembly and is free to push a side surface of the bandsaw blade with a predetermined force so as to prevent vibration of the blade.

This application is a divisional application of Ser. No. 156,819 filedFeb. 17, 1988, now U.S. Pat. No. 4,972,746.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a vibration prevention device for bandsawmachines, which can prevent vibration of a bandsaw blade.

2. Description of the Prior Art

It is known that bandsaw machines generally comprise a saw head assemblyin which a flexible endless bandsaw blade is trained around a pair ofbandsaw blade wheels so that it may perform cutting operations when thewheels are driven.

However, since bandsaw blades used in bandsaw machines are thin elasticblades with many cutting teeth, it is easy for vibrations to occurbetween the bandsaw blade guide device and the bandsaw blade wheel. Inparticular, during cutting of hard-to-cut materials such as stainlesssteel, a great deal of noise is produced, leading to complaints ofpublic disturbance.

To prevent such cutting noise, various measures are taken such asfollows:

(i) increasing the rigidity of the main body of the bandsaw machine,

(ii) attaching a partial cover that is soundproof,

(iii) using a bandsaw blade with unequal pitch, and

(iv) performing discontinuous load cutting such as vibration cutting.

However, a great deal of noise is still produced, creating a need formore countermeasures, especially against medium- and high-frequencynoises.

SUMMARY OF THE INVENTION

Accordingly the main purpose of this invention is to provide a vibrationprevention device for bandsaw machines, which can prevent vibration ofthe bandsaw blade making it possible to reduce noise, and is small insize and can be produced at low cost.

Another purpose of this invention is to provide the vibration preventiondevice which can effectively reduce noise by pushing a side surface ofthe bandsaw blade, with a most suitable force which is adjustableaccording to the size of the workpiece to be cut.

Still another purpose of this invention is to provide a bandsaw bladeguide device which comprises a bandsaw blade guide member for holdingthe bandsaw blade in a vertical orientation, and the vibrationprevention device, and permits force holding the bandsaw blade in thebandsaw blade guide member orientation and force for suppressing noisein the vibration prevention device, to be adjusted independently.

In order to satisfy the above purposes, the vibration prevention devicefor a bandsaw machine that has a saw head assembly in which a flexibleendless bandsaw blade is trained around a pair of bandsaw blade wheelsto cut a workpiece, and guided by a bandsaw blade guide member mountedon a bandsaw guide arm, for holding the bandsaw blade in a verticalorientation, comprises a rolling member which is mounted on the saw headassembly and is free to push a side surface of the bandsaw blade.

According to the present invention, the noise produced by bandsaw bladevibration during cutting is reduced due to vibration suppression. Theeffect is particularly significant when cutting hard-to-cut material andwhen the bandsaw blade is worn. Reductions of 10 to 20 dB in noise levelare typical, with considerable reduction in medium- and high-frequencynoise.

In addition, the vibration prevention device of this invention issmaller, more compact and lower in cost than previous devices.

These and other objects, features and advantages of the presentinvention will be more apparent from the following description of apreferred embodiment taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a horizontal bandsaw machine equipped with afirst embodiment of the present invention.

FIG. 2 is a plan view of the bandsaw blade guide device provided withthe first embodiment of the present invention, the view being taken inthe direction of arrows along line II--II of FIG. 1.

FIG. 3 is a front view, with portions broken away for clarity, of thebandsaw blade guide device provided with the first embodiment of thepresent invention, the view being taken in the direction of the arrowsalong the line III--III of FIG. 2.

FIG. 4 is a sectional view taken in the direction of arrows along lineIV--IV of FIG. 2.

FIG. 5 is a sectional view taken along line V--V of FIG. 2.

FIG. 6 is a plan view, with portions broken away for clarity, of thebandsaw blade guide device provided with a second embodiment of thepresent invention.

FIG. 7 is a front view, with portions broken away for clarity, of thebandsaw blade guide device provided with the second embodiment of thepresent invention, the view being taken in the direction of the arrowalong line VII--VII of FIG. 6.

FIG. 8 is a sectional view taken along line VIII--VIII of FIG. 6.

FIG. 9 is a sectional view taken along line IX--IX of FIG. 6.

FIG. 10 is a plan view, with portions broken away for clarity, of thebandsaw blade guide device provided with a third embodiment of thepresent invention.

FIG. 11 is a front view, with portions broken away for clarity, of thebandsaw blade guide device provided with the third embodiment of thepresent invention, the view being taken in the direction of the arrowalong line XI--XI of FIG. 10.

FIG. 12 is a sectional view taken along line XII--XII of FIG. 10.

FIG. 13 is a sectional view taken along line XIII--XIII of FIG. 10.

FIGS. 14(A) and (B) are fragmentary sectional view taken along lineXIV--XIV of FIG. 11.

FIG. 15 is a plan view of the bandsaw blade guide device provided with afourth embodiment of the present invention.

FIG. 16 is a front view, with portions broken away for clarity, of thebandsaw blade guide device provided with the fourth embodiment of thepresent invention, the view being taken in the direction of the arrowalong line XVI--XVI of FIG. 15.

FIG. 17 is a sectional view taken along line XVII--XVII of FIG. 15.

FIG. 18 is a sectional view taken along line XVIII--XVIII of FIG. 15.

FIG. 19 is a plan sectional view, with portions broken away for clarity,of the bandsaw blade guide device provided with fifth embodiment of thepresent invention.

FIG. 20 is a sectional view taken along line XX--XX of FIG. 19.

FIG. 21 is a sectional view taken along line XXI--XXI of FIG. 19.

FIG. 22 is the bandsaw blade guide device provided with a plan view,with portions broken away for clarity, of a sixth embodiment of thepresent invention.

FIG. 23 is a front view, with portions broken away for clarity, of thebandsaw blade guide device provided with the sixth embodiment of thepresent invention, the view being taken in the direction of the arrowalong line XXIII--XXIII of FIG. 22.

FIG. 24 is a sectional view taken along line XXIV--XXIV of FIG. 22.

FIG. 25 is a sectional view taken along line XXV--XXV of FIG. 22.

FIG. 26 is a plan view, with portions broken away for clarity, of thebandsaw blade guide device provided with a seventh embodiment of thepresent invention.

FIG. 27 is a front view of the bandsaw blade guide device provided withthe seventh embodiment of the present invention, the view being taken inthe direction of the arrow along line XXVII--XXVII of FIG. 26.

FIG. 28 is a sectional view taken along line XXVIII--XXVIII of FIG. 26.

FIG. 29 a plan view, with portions broken away for clarity, of thebandsaw blade guide device provided with a eighth embodiment of thepresent invention.

FIG. 30 is a front view of the bandsaw blade guide device provided witha ninth embodiment of the present invention.

FIG. 31 is a sectional view taken along line XXXI--XXXI of FIG. 30.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1, a horizontal bandsaw machine 1 which is shownas an example comprises a box-shaped base 3 and a cutting head 5. Thecutting head 5 is supported on the base 3 through a hinge pin 7 so thatit is free to pivot upon the hinge pin 7, and move up and down.

On top of the base 3 is provided a work table 9 on which a work piece Wto be cut can be placed. The work table 9 is provided with a vise device11 which has a fixed vise jaw 11f and a movable vise jaw 11m to grip thework piece W therebetween.

The cutting head 5 has housing sections 13 and 15 on either sidethereof. The tops of the housing sections 13 and 15 are connected by thebeam member 17 on which is mounted on a control box 19.

The housing sections 13 and 15 of the cutting head 5 have a drive wheel21 and a driven wheel 23, which are disposed within the housing sections13, 15, and mounted on the shafts 25 and 27, respectively. An endlessbandsaw blade 29 as a cutting blade is trained around the drive wheel 21and the driven wheel 23. Thus, when the drive wheel 21 turns around, thecutting blade 29 is driven to cut the work piece W.

The cutting blade 29 is supported and guided within the cutting areawhere the work piece W will be cut, such that the tooth tips pointvertically downward, by a pair of bandsaw blade guide devices 35 and 37which are mounted on the lower ends of the fixed guide arm 31 and themovable guide arm 33, respectively.

The fixed guide arm 31 and movable guide arm 33 are mounted on a guidemember 39 that is fixed to the beam member 17. The fixed guide arm 31 ismounted fixedly on the guide member 39. The movable guide arm 33 ismovably mounted on the guide member 39 so that position thereof can beadjusted to conform to the size of the work piece W.

In addition, between the base 3 and cutting head 5, a raising andlowering cylinder 41 equipped with a piston rod 43 is provided.Therefore, when pressurized oil is forced into the piston side chamberof the raising and lowering cylinder 41, causing the piston rod 43 toextend, the cutting head 5 is raised. Conversely, when pressurized oilis removed from the piston side chamber of the raising and loweringcylinder 41, causing the piston rod 43 to be shortened, the cutting headis lowered by its own weight. Consequently, by installing a suitablecontrol valve in the oil ejection pipe connected to the piston sidechamber of the raising and lowering cylinder 41, and by suitablyadjusting this control valve, the cutting operation of the work piece Wby the cutting blade 29 can be controlled.

Now, let us explain configurations of the bandsaw blade guide devices 35and 37 provided with embodiments of vibration prevention device of thepresent invention. The bandsaw blade guide devices 35 and 37, which areattached to the lower ends of the fixed guide arm 31 and the movableguide arm 33, respectively, have basically the same configuration;therefore this explanation will be confined to the bandsaw blade guidedevice 37 which is attached to the lower end of the movable guide arm33. Note that the same parts have the same numbers in the explanationsof various embodiments which follow.

First, the bandsaw blade guide device 37 provided with a firstembodiment of the present invention will be explained. As shown in FIG.2 and FIG. 3, a first holder 45 and a second holder 47 of the bandsawblade guide device 37 are fixed to lower end of the movable guide arm 33by means of bolts 49, 51 so that the holders 45, 47 hold a side wall ofthe movable guide arm 33 therebetween. Moreover, a spherical lever 53 ismounted within the air gap sections 33a, 45a, 47a formed in the movableguide arm 33, the first holder 45 and the second holder 47,respectively, here the air gap sections 33a, 45a, 47a is formed at aposition near the bolt 49 between the bolt 49 and bolt 51 in thevertical direction. The spherical lever 53 is supported at the sphericalsurface 53A by the concave spherical bearing ring 55 mounted within thefirst holder 45.

As shown in FIG. 2, FIG. 3 and FIG. 4, a roller shaft 59 is installed infront of the second holder 47, for supporting the first roller 57, asthe rolling member. More specifically, the roller shaft 59 is supportedat midportion thereof on the second holder 47 by means of a bolt 61which is in threaded engagement with the second holder 47 through thehole 59a formed in the roller shaft 59; here, as is clear from FIG. 4,the hole 59a is formed so as for the radius thereof to be slightlylarger than that of the bolt 61 except neck portion 61a thereof, wherethe both radii are same, so that the top and bottom ends of the rollershaft 59 are free to pivot right and left in FIG. 4 upon a neck portion61a of the bolt 61. As shown in FIG. 4, the first roller 57 is supportedto the roller shaft 59 through the aligning bearing 69 so that it isautomatically aligned and free to rotate.

A set screw 63 is provided on an upper portion of the roller shaft 59,one end thereof being screwed into the screw hole 65 formed in an upperportion of the roller shaft 59. And a tip of another end of the setscrew 63 abuts against left spherical end 53L of the spherical lever 53.Thus, a distance between the left spherical end 53L of spherical lever53 and the upper portion of the roller shaft 59 can be adjusted byrotating the set screw 63. The set screw 63 will be fixed to the rollershaft 59 by the lock screw 67.

As shown particularly, in FIGS. 2 and 5, the first holder 45 has a yokesection 45b at a bottom portion thereof and a vertical groove 89 at afront portion thereof. Within an air gap 45c formed between the yokesection 45b a guide roller 85 for guiding a back surface of the bandsawblade 29 is mounted, supported by groove 89 so as to be free to rotate.

A fixed guide block 77 is fixed to one of the lower ends of the yokesection 45b of the first holder 45 by means of a bolt 79 to contact oneside of the bandsaw blade 29. In addition, a movable guide block 81 isinstalled on the other lower end of the yoke section 45b to contact tothe other side of the bandsaw blade 29; the movable guide block 81 ismounted on the yoke section to be movable in the right and leftdirection in FIG. 5, by means of horizontal protruding pins 83 that arefixed to the first holder 45. Therefore the movable guide block 81 canhold and guide the bandsaw blade 29 between itself and the fixed guideblock 77.

As shown in FIGS. 2 and 5, within the vertical groove 89, a stripeshaped clamp spring 97 is mounted, with a bottom end thereof abuttingagainst the movable guide block 81. And an upper end of the clamp spring97 is engaged with a protrusion 71T of a freely movable body 71 mountedon an upper portion of the first holder 45. That is to say, on an upperportion of the first holder 45 a horizontal hole 45d to which a rightspherical end of the spherical lever 53R extends, is formed. Within thehorizontal hole 45d, a freely movable body 71 having a center hole 73and a protrusion 71T is mounted, with the center hole 73 mating with theright spherical end of the spherical lever 53R. And an upper end of theclamp spring 97 is engaged with the protrusion 71T of the freely movablebody 71 mounted on an upper portion of the first holder 45.

A cam member 95 is rotatably mounted within the vertical groove 89 bymeans of shaft pin 91 to press the center section of the clamp spring 97rearward. And on the cam member 95 a clamp lever 93 is provided torotate the cam member 95.

In the above configuration, when the clamp lever 93 is rotated to theposition shown by the solid line in FIG. 5, the cam member 95 pressesagainst the center section of the clamp spring 97. Then, the bottom endof the clamp spring 97 and the movable guide block 81 are pressed towardthe fixed guide block 77 to hold the bandsaw blade 29 in a verticalorientation as shown by the solid line in FIG. 5.

Meanwhile, as shown in FIG. 2, when the clamp lever 93 is rotated to theabove-mentioned position, the upper end of the clamp spring 97 and thefreely movable body 71 are pressed rearward, the spherical lever isrotated counterclockwise in FIG. 2, and the set screw 63 mounted on theupper portion of the roller shaft 59 is pressed forward. Thereupon, asis understood from FIG. 4, the upper end of the roller shaft 59 ispressed forward, the roller shaft 59 is rotated clockwise in FIG. 4around the neck portion of the bolt 61a, and the first roller 57 ispressed backward through an aligning bearing 69 to press strongly anduniformly the bandsaw blade 29.

In addition, as shown in FIG. 5, when the cam member 95 is pressingagainst the center section of the clamp spring 97, vibration of the bandsaw 29 will cause the movable guide block 81 to separate from the fixedguide block 77. When this happens, the clamp spring 97 tends to rotateclockwise in FIG. 5 around the point where the cam member 95 pressesagainst it, causing the first roller 57 to press against the bandsawblade 29 more strongly to suppress the vibrations thereof.

Conversely, when the first roller 57 is pressed to the forward in FIG. 4due to vibration of the bandsaw blade 29, the force pressing on themovable guide block 81 becomes stronger. Consequently, the movable guideblock 81 and the first roller 57 will in cooperation with each other tosuppress vibrations of the bandsaw blade 29 effectively. Thus, the noiseproduced during cutting operation by the bandsaw blade 29, especiallymedium- and high-frequency noise, can be reduced. The effect isparticularly noticeable in cutting of materials that are hard-to-cut andwhen the bandsaw blade is worn; the present inventors have confirmedthat the noise reduction can be as great as 10 to 20 dB.

On the other hand, when the clamp lever 93 is rotated to the clamp openposition shown by the two-dot chain line in FIG. 5, the pressure of thecam member 95 on the clamp spring 97 is released, and the reaction forceof the bandsaw blade 29 causes the movable guide block 81 to separatefrom the fixed guide block 77. At the same time, the freely moving body71 coupled to the clamp spring 97 is no longer pressed rearward and canmove forward. Then, through the spherical lever 53, the top end of theroller shaft 59 can move rearward, and its bottom end can move forwardto separate from the bandsaw blade 29.

Thus, the bandsaw blade 29 can be attached to or removed from the guidedevice 37 by one-touch operation of the clamp lever 93, and when thebandsaw blade 29 is attached to the guide device 37, the bandsaw blade29 is held in a vertical orientation and the vibration thereof iseffectively suppressed by the fixed and movable guide blocks 77, 81 andthe first roller 57.

Moreover, since there is no member opposite the first roller, theconstruction is simplified; at the same time, because of theabove-mentioned reason, a distance between the movable vise jaw 11m andthe bandsaw blade 29 is reduced, so that the excess material on the workpiece W can be made as small as possible, and the work piece W can beclamped close to the cutting position to make the clamping secure.

A bandsaw blade guide device 37 provided with a second embodiment of thepresent invention will now be explained, referring to FIGS. 6 through 9.

As shown in FIGS. 6-9, a first holder 45 of the bandsaw blade guidedevice 37 is attached on a side wall of the bottom end of the guide arm33 by means of the two bolts 49 and 51 so that it can be adjusted in thevertical direction, wherein the first holder 45 has a yoke section 45bat a bottom portion thereof.

On a front portion of the first holder 45, a L-shaped support block 99is pivotally supported by a support pin 101. A roller shaft 59 issupported on one end of the L-shaped support block 99. A first roller 57is attached to a lower end of the roller shaft 59 through the aligningbearing 69 so that it is automatically aligned and free to rotate, asshown in FIG. 8.

A small-diameter second roller 103 is fixed to a rear portion of thefirst holder 45 through a bearing by a bolt-type shaft 105 so that itfaces the first roller 57 across the bandsaw blade 29.

Consequently, the first roller 57 can be moved toward or away from thefixed second roller 103 by pivot of the support block 99 upon thesupport pin 101.

Now as shown in FIG. 9, a guide roller 85 is rotatably mounted within anair gap 45c between the yoke section 45b of the first holder 45 by meansof a bolt 87, so as to guide the back portion of the bandsaw blade 29. Afixed guide block 77 is fixed to one side of a lower end of the yokesection 45b of the first holder 45 by means of a bolt 79 to contact oneside of the bandsaw blade 29. A movable guide block 81 is mounted on theother side of the lower end of the yoke section 45b to contact the otherside of the bandsaw blade 29. Specifically the movable guide block 81 issupported by the pin 107 which is mounted on the other side of the lowerend of the yoke section so that it is free to move right and left inFIG. 9 with respect to the first holder 45. Therefore, the movable guideblock 81 is free to move toward or away from the fixed guide block 77 tohold and release the bandsaw blade 29 between it and the fixed guideblock 77.

A cylinder, for example a hydraulic cylinder 109, is fastened to a frontportion of the support block 99 by means of several bolts 111 shown inFIG. 7. The hydraulic cylinder 109 comprises piston rod 117 which ismovable in left and right direction in FIG. 9 and abutting against thepin 107. A pipe 115 is attached to the hydraulic cylinder 109 through ajoint 113.

In the configuration described above, by supplying pressurized oil froma hydraulic drive source, which is not shown, to the pipe 115, thepiston rod 117 in the hydraulic cylinder 109 is moved rearward(rightward in FIG. 9). Then the piston rod 117 presses the movable guideblock 81 against the fixed guide block 77 by means of motion transmittedthrough the pin 107 to hold the bandsaw blade 29 in a verticalorientation as shown by the solid line in FIG. 9.

Meanwhile, when the piston rod 117 in the hydraulic cylinder 109 movesin the above-mentioned direction, reaction force due to the press actionof the hydraulic cylinder 109 causes the support block 99 to pivotclockwise in FIG. 6 upon the support pin 101; and the pivot of thesupport block 99 causes the first roller 57 to be moved rearward. Thusthe bandsaw blade 29 is held strongly between the first roller 57 andthe second roller 103.

In addition, when the movable guide block 81 is pressed against thefixed guide block 77, the clamping force on the bandsaw blade 29 can beadjusted by adjusting the oil pressure in the hydraulic cylinder 109.Consequently, even if the bandsaw blade 29 vibrates, the noise generatedby vibrations of the bandsaw blade 29 can be effectively suppressed byoptimally adjusting the oil pressure.

Also, it is easy for the bandsaw blade 29 to be attached to or removedfrom the guide device 37, since the bandsaw blade 29 will besimultaneously held between the first and second rollers 57, 103 andbetween the fixed and movable guide blocks 77, 81, by supplying orremoving oil to or from the hydraulic cylinder 109.

In addition, in the second embodiment described above, since theclamping is done by oil pressure, the clamping force is stable and themachine is made up of relatively few parts.

Although the second roller 103 is used for a supporting member facingthe first roller 57 across the bandsaw blade 29, for supporting thebandsaw blade 29 between itself and the first roller, alternatively, asupporting block similar to the fixed guide block 77 may be used for thesupporting member.

Moreover, even if the aligning bearing is not used for the first roller57, a uniform pressure force can be applied to the bandsaw blade 29since the support block 99 always rotates horizontally and the rollershaft 59 is never tilted.

In the embodiment described above, the sizes of the movable first roller57 and the fixed second roller 103 may be made the same or evenreversed. Or, the fixed second roller 103 may be dispensed with.

A bandsaw blade guide device provided with a third embodiment of thepresent invention will now be described, based on FIGS. 10 through 14.

As is shown in FIGS. 10-13, on a side wall of the lower end of themovable guide arm 33 is attached a first holder 45 by means of the twobolts 49 and 51, so as for the position thereof to be adjustable in thevertical direction, wherein the first holder 45 has a yoke section 45bat a bottom portion thereof and a vertical groove 89 at a front portionthereof.

As shown particularly in FIGS. 10, 11 and 12, a rectangular supportblock 99 is pivotally mounted on a front of the first holder 45 by asupport pin 101. A plate spring 119 is fixed to a front of the supportblock 99 at a left end thereof by means of a bolt 123. As shown in FIGS.10 and 11, a mid-portion of the plate spring 119 is adjustably fixed tothe support block 99 by a first adjustment bolt 121. The right end ofthe plate spring 119 abuts against the cam member 125 which will bediscussed below. A roller shaft 59 is attached to one side of therectangular support block 99. And a first roller 57 is mounted on abottom portion of the roller shaft 59 through aligning bearing 69 shownin FIG. 12.

A small-diameter second roller 103 is fixed to a rear portion of thefirst holder 45 by means of a bolt-shaft 105, to face the first roller57 across the bandsaw blade 29.

Consequently, when the plate spring 119 and the support block 99 pivotupon the support pin 101, the first roller 57 can be moved toward oraway from the fixed second roller 103.

As shown in FIG. 13, a guide roller 85 is mounted within the air gap 45cbetween the yoke section 45b of the first holder 45 by the bolt shaft 87to guide the back portion of the bandsaw blade 29.

A fixed guide block 77 is fixed to one side of the bottom end of theyoke section 45b of the first holder 45 by the bolt 79 to contact oneside surface of the bandsaw blade 29. The movable guide block 81 isinstalled on the other side of the bottom end of the yoke section 45b tocontact the other side surface of the bandsaw blade 29; here the movableblock 81 is supported on the first holder 45 by the two horizontallyprotruding pins 83 so as to be free to move toward or away from thefixed guide block 77.

As is clear from FIGS. 10, 11 and 13, a clamp spring 97 is mountedwithin the vertical groove 89 of the first holder 45 with the bottom endthereof abutting against the movable guide block 81. Specifically, theclamp spring 97 is supported at the upper portion thereof by aprotrusion 71T of a second adjustment bolt 71; the second adjustmentbolt is in threaded engagement with an upper portion of the first holder45 and is movable in right and left direction in FIG. 13 by rotationthereof.

Cam members 95 and 125 which are integrated to each other are rotatablymounted within the vertical groove 89 by a shaft pin 91 to press acenter section of the clamp spring 97 rearward and the right end of theclamp spring 119 forward, respectively. A clamp lever is mounted on theclamp spring 119. A stopper 127 is installed to limit the clockwiserotation range of the clamp lever 93 in FIGS. 14(A), (B).

Therefore, when the clamp lever 93 rotates to the position shown by thetwo-dot long and two short dashes line in FIG. 13, as shown in FIGS.14(A) and 14(B), the cam member 95 is removed from the clamp spring 97and the other cam member 125 loosens its pressure on the plate spring119.

In the configuration described above, when the clamp lever 93 is rotatedto the position (FIG. 14 (A)) shown by the solid line in FIG. 13, thecam lever 95 presses against the center section of the clamp spring 97to push the movable guide block 81 toward the bandsaw blade 29, holdingthe same in a vertical orientation. Meanwhile, the rotation of the clamplever 93 causes the other cam member 125 to push the right end of theplate spring 119 forward. Then, the other end of the plate spring 119causes the support block 99 to rotate clockwise in FIG. 10 upon thesupport pin 101 and the first roller 57 is pushed backward to push thebandsaw blade 29 strongly against the second roller 103.

When the clamp lever 93 is rotated to the position shown by the two-dotlong and two short line in FIG. 13, the pressure of the cam member 95against the clamp spring 97 is released. Then the reaction force of thebandsaw blade 29 causes the movable guide block 81 to separate from thefixed guide block 77. In addition, the rotation of the clamp lever 93releases the pressure of the other cam member 125 against the platespring 119, and the first roller 57 separates from the bandsaw blade 29.

Thus, the bandsaw blade 29 can be attached to or removed from the guidedevice 37 by one-touch operation of the clamp lever 93, and when thebandsaw blade 29 is attached to the guide device 37, the bandsaw blade29 is held in a vertical orientation and the vibration thereof iseffectively suppressed by the fixed and movable guide blocks 77, 81 andthe first and second rollers 57, 103.

Moreover, by rotating the adjustment bolts 71 and 121 suitably, forceproduced by the guide blocks 77, 81 to hold the bandsaw blade 29 in avertical orientation, and force produced by the rollers 57, 103 tosuppress vibrations of the bandsaw blade can be set independently ofeach other, permitting both functions to be optimized.

Although the second roller 103 is used for a supporting member facingthe first roller 57 across the bandsaw blade 29, for supporting thebandsaw blade 29 between itself and the first roller, alternatively, asupporting block similar to the fixed guide block 77 may be used for thesupporting member.

The relative sizes of the first roller 57 and the second roller 103 maybe opposite to what they were in the above explanation.

A bandsaw blade guide device provided with a fourth embodiment of thepresent invention will now be explained referring to FIGS. 15 through18.

The bandsaw blade guide device provided with the fourth embodiment issimilar to that provided with the second embodiment shown in FIGS. 6-9,in the mechanism to hold the bandsaw blade in a vertical orientation;i.e. as shown particularly in FIG. 18 on the first holder 45, in orderto guide a back portion of the bandsaw blade 29 a guide roller 85 ismounted, and in order to hold the bandsaw blade 29 in a verticalorientation a fixed guide block 77, a movable guide block 81, a pin 107,hydraulic cylinder 109 having piston rod 117, a joint 113 and a pipe 115are mounted.

However, it is different from the guide device provided with the secondembodiment in the mechanism to prevent the vibration of the bandsawblade 29. That is to say, as shown particularly in FIG. 17, a horizontalhole 129 is formed within a center portion of the first holder 45. Asliding piece 131 formed with a slot 133 is inserted into the hole 129so that it is freely to slidable in the right and left direction in FIG.17. A pin 135 fixed to the first holder 45 is inserted through the slot133, so that the movement of the sliding piece 135 is limited by the pin135. A roller shaft 59 is integrated with the bottom portion of thesliding piece 131. A first roller 57 is mounted on the roller shaftthrough aligning bearing 69.

In addition, a hydraulic cylinder 137 for moving the sliding piece 131,is attached to the first holder 45 by means of a plurality of bolts 139(see FIG. 16); that is to say, a piston rod 145 is installed inside thehydraulic cylinder 137 so that it is free to move right and left in FIG.17, and one end of the piston rod 145 is coupled to the sliding piece131 by a pin 147. To the hydraulic cylinder 137, a pipe 143 forsupplying a pressurized oil is attached through a joint 141.

In the configuration described above, when pressurized oil is suppliedfrom a hydraulic drive source, which is not shown in the figures, to thepipe 143, the piston rod 145 in the hydraulic cylinder 137 movesrearward (leftward in FIG. 17). Then, the roller shaft 59 and the firstroller 57 integrated with the sliding piece 131 is moved rearward tostrongly push the bandsaw blade 29 against the fixed second roller 103.

Similarly, as to the mechanism for holding the bandsaw blade 29 in thevertical orientation which is particularly shown in FIG. 18, whenpressurized oil is supplied from the hydraulic drive source, which isnot shown, to the pipe 115 of the hydraulic cylinder 109, the piston rod117 inside the hydraulic cylinder 109 is driven rearward (rightward inFIG. 18). Then the moving guide block 81 is pushed through the pin 107against the fixed guide block 77 to hold the bandsaw blade 29 in avertical orientation.

Consequently, if the same supply valve is used to control thepressurized oil to supply to the pipe 115 and the pipe 143, the movingguide block 81 and the first roller 57 will set at the same time, sothat the bandsaw blade 29 will be held in a vertical orientation andvibrations suppressed at the same time.

Although the second roller 103 is used for a supporting member facingthe first roller 57 across the bandsaw blade 29, for supporting thebandsaw blade 29 between itself and the first roller, alternatively, asupporting block similar to the fixed guide block 77 may be used for thesupporting member.

In the embodiment discussed above the relative sizes of the movablefirst roller 57 and the fixed second roller 103 may be reversed, or theymay be the same size. Also it is possible to dispense with the fixedsecond roller 103.

Let us now explain a bandsaw blade guide device 37 provided with a fifthembodiment, referring to FIGS. 19 through 21.

As shown in FIGS. 19-21, the bandsaw blade guide device provided withthe fifth embodiment is similar to that provided with the fourthembodiment explained above. The guide device provided with the fifthembodiment is different from that provided with the fourth embodiment,in that in the former, the pressure forces from hydraulic cylinders aretransmitted to the movable guide block and the movable first rollerthrough levers.

That is to say, as shown particularly in FIGS. 19, 20, a shaft 45d isinstalled on a bottom portion the first holder 45. A first lever member45e is rotatably supported on the shaft 45d. A roller shaft 59 forsupporting a first roller 57 is mounted on the lever member 45e. Aspring 45g is elastically mounted between the lever member 45e and thefirst holder 45. Therefore, the lever member 45e is biased and caused torotate clockwise in FIG. 19 upon the shaft 45d. A hydraulic cylinder 45fis mounted on the front of the first holder 45 in order to rotate thelever member 45e in the counterclockwise direction in FIG. 19 and causethe first roller to move toward the bandsaw blade 29.

In addition, a second roller 103 is mounted on a rear portion of thefirst holder 45 to face the first roller 57 across the bandsaw blade 29.

Consequently, by supplying pressurized oil from a hydraulic drivingsource, which is not shown, to the hydraulic cylinder 45f, the levermember 45e rotates clockwise in FIG. 19. And the first roller 57approaches the second roller 103 through the bandsaw blade 29, so thatthe bandsaw blade 29 is holded between the first roller 57 and thesecond roller 103.

When the pressurized oil is removed from the hydraulic cylinder 45f, theelastic force of the spring 45g causes the lever member 45e to berotated counterclockwise in FIG. 19, so that the first roller 57 isremoved from the bandsaw blade 29 and the second roller 103, releasingthe bandsaw blade 29 from the holding.

Meanwhile, as shown in FIG. 21, a fixed guide block 77 and a movableguide block 81 are mounted on a yoke section of the first holder 45 tohold the bandsaw blade 29 in a vertical orientation. A pin 107 ismounted on one end of the yoke section to press the movable guide block81 toward the bandsaw blade 29. A lever member 45h is pivotally mountedon a front portion of the first holder 45 by means of a shaft 45i, witha bottom end the shaft 45i abutting a front end of the pin 107. A spring45j is mounted between bottom end of the lever member 45h and that ofthe first holder 45 to bias and cause the lever member 45h to be rotatedclockwise in FIG. 21 upon the shaft 45i.

In addition, a hydraulic cylinder 45k is mounted on the upper portion ofthe first holder 45 with a piston thereof abutting against an upper endof the lever member 45h, in order to rotate the lever member 49hcounterclockwise in FIG. 21 upon the shaft 45i.

Consequently, by supplying pressurized oil from a hydraulic drivingsource, not shown in the figures, to the hydraulic cylinder 45k, thelever member 45h is rotated counterclockwise in FIG. 21 upon the shaft45i to move the pin 107 and the movable guide block 81 toward thebandsaw blade 29 and the fixed guide block 77, holding the bandsaw blade29 in a vertical orientation between the movable guide block 81 and thefixed guide block 77.

When pressurized oil is removed from the hydraulic cylinder 45k, theelastic force of the spring 45j causes the lever member 45h to berotated clockwise in FIG. 21 upon the shaft 45i, separating the movableguide block 81 from the bandsaw blade 29 and the fixed guide block 77,releasing the bandsaw blade 29 from the holding.

Although the second roller 103 is used for a supporting member facingthe first roller 57 across the bandsaw blade 29, for supporting thebandsaw blade 29 between itself and the first roller, alternatively, asupporting block similar to the fixed guide block 77 may be used for thesupporting member.

Now let us explain a bandsaw blade guide device 37 provided with a sixthembodiment of the present invention, referring to FIGS. 22 through 25.

As shown particularly in FIGS. 23 and 25, the mechanism for holding thebandsaw blade 29 in a vertical orientation has a configuration similarto those for the bandsaw blade guide device having the second and fourthembodiments of the present invention described above. That is to say,when pressurized oil is supplied from a hydraulic driving source, whichis not shown, to a pipe 115, a piston rod 117 in a hydraulic cylinder109 moves rearward (rightward in FIG. 25). Then, a moving guide block 81is pushed through a pin 107 against the fixed guide block 77 to hold thebandsaw blade 29 in a vertical orientation between the movable and thefixed guide blocks 81, 77.

On the other hand, a mechanism for suppressing the vibration of thebandsaw blade 29 is as follows.

As shown particularly in FIGS. 22 and 24, a shaft 149 is rotatablymounted on a left portion of a front of the first holder 45. And aroller shaft 59 is supported at an off-center position of the shaft 149.On the roller shaft 59, a first roller 57 is mounted through an aligningbearing 69. A second roller 103 is mounted on a left portion of a rearof the first holder 45 through a shaft 105 to face the first roller 57across the bandsaw blade 29. Therefore, by rotating the shaft 149 thefirst roller 57 is moved toward and away from the bandsaw blade 29 andthe second roller 103.

A cam member 153 is attached to the shaft 149 through a return spring151, so that the return spring 151 biases and causes the cam member 153and the shaft 149 to rotate upon the axis of the shaft 149. A hydrauliccylinder 155 having a piston rod 163 that is free to move back andforth, is mounted on a rear portion, which is above the second roller103, of the first holder by means of a plurality of bolts 157, so thatone end of the piston rod 163 abuts against the cam member 153. A pipe161 is attached to the hydraulic cylinder 155 through a joint 159.

In the configuration described above, when pressurized oil is suppliedfrom a hydraulic drive source, which is not shown, to the pipe 161, thepiston rod 163 in the hydraulic cylinder 155 moves forward (downward inFIG. 22). The motion of the piston rod 163 acts on the shaft 149 throughthe cam member 153, causing it to rotate clockwise in FIG. 22. When theshaft 149 rotates, the first roller 57 which is at the off-centerposition of the shaft 149 moves backward, pushing the bandsaw blade 29strongly against the fixed second roller 103 to suppress the vibrationof the bandsaw blade 29.

When pressurized oil is removed from the pipe 161, the action of thereturn spring 151 causes the piston rod 163 and the cam member 153 toreturn to their original positions, and the shaft 149 rotatescounterclockwise in FIG. 22 causing the first roller 57 to move forward(downward in FIG. 22), returning to its original position.

Also, by using the same supply valve to control the supply ofpressurized oil to the pipe 115 and the pipe 161, the moving guide block81 and the first roller 57 can be made to act at the same time, so thatthe bandsaw blade 29 is easily attached to and removed from the guidedevice 37; moreover a ratio of the pressure on the movable guide block81 to hold the bandsaw blade 29 in the vertical orientation and thepressure on the first roller to suppress vibration of the bandsaw blade29, is most suitably adjusted.

In the configuration described above, it is possible to dispense withthe return spring 151; in this case the piston rod 163 may be engagedwith the cam 153, and a return spring 169, shown in FIG. 22, may bedisposed within the hydraulic cylinder 155. In addition the rotation ofthe eccentric shaft 149 could be driven by some means other thanpressurized oil, such as a spring.

Although the second roller 103 is used for a supporting member facingthe first roller 57 across the bandsaw blade 29, for supporting thebandsaw blade 29 between itself and the first roller, alternatively, asupporting block similar to the fixed guide block 77 may be used for thesupporting member.

Also, the relative sizes of the movable first roller 57 and the fixedsecond roller 103 can be reversed, or they can be the same size.Further, it is possible to dispense with the fixed second roller 103.

Now let us explain a bandsaw blade guide device 37 provided with aseventh embodiment of the present invention, referring to FIGS. 26through 28.

As shown in FIGS. 26, 27, and 28, there is provided at a bottom portionof the first holder 45, a yoke section 45b which is similar to that ofFIGS. 5, 9, 13, 19, 21, 25, is formed. A fixed guide block 77 is mountedon one side of the yoke section of the first holder 45b. A movable guideblock 81 is mounted on the other side of the yoke section of the firstholder 45b by a plurality of guide pins 171, so as freely to move backand forth. On a left side portion of the movable guide block 81, a platespring 165 is mounted by a plurality of bolts 169. And a roller shaft 59is supported at a tip of the plate spring 165 by a plurality bolts 167.A first roller 57 is mounted on the roller shaft 57 through an aligningbearing 69. Also a second roller 103 is mounted on a left side portionof the one side of the yoke section of the first holder 45b by a shaft105, facing the first roller 57 across the bandsaw blade 29.

As can be seen from FIGS. 26 and 27, a hydraulic cylinder 109 providedwith piston rod 117 through a return spring 173, is mounted on the otherside of the yoke section of the first holder 45b so that the piston rod117 abuts against the movable guide block 81.

In the configuration described above, by supplying pressurized oil froma hydraulic drive source, which is not shown to the pipe 115, the pistonrod 117 in the hydraulic cylinder 109 overcomes the force of the spring173 to move rearward (upward in FIG. 26) and push both the movable guideblock 81 and the first roller 57 rearward. Here, firstly, the firstroller 57 contacts the bandsaw blade 29, and then the plate spring 165deforms until the movable guide block 81 contacts the bandsaw blade 29,pushing the first roller 57 against the bandsaw blade 29. This actionholds the bandsaw blade 29 in a vertical orientation and also suppressesvibrations thereof.

By removing the pressurized oil, the return force of the spring 173pushes the piston rod 117 forward (downward in FIG. 26), and the firstroller 57 and the movable guide block 81 return forward to theiroriginal positions.

Although the second roller 103 is used for a supporting member facingthe first roller 57 across the bandsaw blade 29, for supporting thebandsaw blade 29 between itself and the first roller, alternatively, asupporting block similar to the fixed guide block 77 may be used for thesupporting member.

Now let us explain a bandsaw blade guide device 37 provided with aeighth embodiment of the present invention, referring to FIG. 29.

The bandsaw blade guide device provided with the eighth embodiment hasalmost the same configuration as that provided with seventh embodiment,but, as shown in FIG. 29, a right end of the plate spring 165 is notfixed to a movable guide block 81 by the bolts 169 in the guide deviceprovided with the eighth embodiment, instead, the plate spring 165 isattached to the movable guide block 81 by a plurality of guide pins 171.Thus, in the present guide device, the movement of the piston rod 117presses the movable guide block 81 rearward through the plate spring165.

Other than this change, the configuration is basically the same as thatwith the seventh embodiment.

In the configuration described above, since the piston rod 117 pushesagainst the movable guide block 81 near the middle of the block, even ifthe first roller 57 is broken the bandsaw blade 29 will be held firmlyin place.

Also, the pressure forces of the first roller 57 and the movable guideblock 81 can be set to optimum values by adjusting the pressure of theoil supplied to the hydraulic cylinder 113 and varying the bendingstrength of the plate spring 165 within the horizontal plane.

Let us now explain a ninth embodiment of the present invention,referring to FIGS. 30 and 31.

As shown in FIG. 30 and FIG. 31, a movable guide arm 33 which will holdthe bandsaw blade 29 to twist the same by 90° while guiding it, isattached to the guide member 39 of the cutting head 1, both guide member39 and cutting head 1 being shown in FIG. 1. A vibration preventiondevice 175 is attached, for example, to the housing 15 for enclosing thedriven wheel 23, both of which are shown in FIG. 1.

Explaining the vibration prevention device 175 in more detail, theL-shaped support bracket 177 in the vibration prevention device 175 isattached to the housing 15 by a plurality of bolts 179 so that it isinstalled between the driven wheel 23 and the movable guide arm 33;preferably it is installed at about a mid-portion of the driven wheel 23and the movable guide arm 33 to effectively suppress the vibration ofthe bandsaw blade 29. A shaft 181 is attached to a tip of the supportbracket 177 by a nut 183. A roller 184 is freely rotatably supported onthe shaft 181 so as to push the bandsaw blade with a predeterminedstrong force; a strength of the force depends on the radius of theroller 184, but it is preferably larger than 10% of that for twisting inthe guide arms and more preferably between 40% and 100% of the same.

In the configuration described above, the bandsaw blade 29 smoothly runsbetween bandsaw blade wheels 21 and 23 while being guided by the movableguide arm 33, and at the same time its vibrations are suppressed by theroller 183 of the vibration prevention device 175.

In the above disclosed embodiment, instead of the roller 183, a pair ofrollers which will hold the bandsaw blade therebetween may be used.

Although a preferred embodiments are specifically illustrated anddescribed herein, it will be appreciated that many modifications andvariations of the present invention are possible in light of the aboveteachings and within the purview of the appended claims withoutdeparting from the spirit and intended scope of the invention.

What is claimed is:
 1. A bandsaw blade guide device which is mounted onone end of the bandsaw guide arm for guiding the bandsaw blade that runsbetween a pair of bandsaw blade wheels, comprising:a first supportingmember which is mounted on guide arm and is free to contact one sidesurface of the bandsaw blade; a second supporting member which ismounted on the guide arm facing the first supporting member across thebandsaw blade and is free to contact a first portion of the other sidesurface of the bandsaw blade; a third supporting member comprising aroller which is mounted on the guide arm, separated from the secondsupporting member along a direction of travel of the bandsaw blade andis free to contact a second portion of the other side surface of thebandsaw blade; a fourth supporting member comprising a roller which ismounted on the guide arm facing the third supporting member across thebandsaw blade and is free to contact the one side surface of the bandsawblade; and a pressure applying means mounted on the guide arm forapplying pressure to the second supporting member and the thirdsupporting member separately to hold the bandsaw blade between the firstand the second supporting member and the third and fourth supportingmembers, respectively, the pressure applying means applying a pressureto the third supporting member higher than 40% of that applied to thesecond supporting member; and said third and fourth supporting membersbeing positioned upstream of said first and second supporting members,wherein the pressure applying means comprises: a first hydrauliccylinder for pressing the second supporting member against the firstsupporting member; a lever for pressing the third supporting memberagainst the fourth supporting member; and a second hydraulic cylinder toactuate said lever.
 2. The bandsaw blade guide device according to claim1 further comprising:a shaft which is mounted on the guide arm so thatit is free to rotate and supports the third supporting member at anoff-centered position thereof, wherein the third supporting member ispushed against the side of the bandsaw blade by the rotation of theshaft which is caused by pressure from the second hydraulic cylinder.